1. Field of the Invention
The present invention generally relates to a disk chucking device for chucking a disk placed on a turntable of a disk player such as an optical disk player or a magnetooptical disk player. More particularly, the present invention relates to a disk chucking device suitable for reducing the thickness of the disk player.
2. Description of the Related Art
Hitherto, a disk chucking device illustrated in, for example, FIGS. 5, 6A and 6B has been used for chucking an optical disk, such as a compact disk (trade name), on a turntable.
As shown in FIG. 5, this chucking device 10 has a center boss 12 that is disposed above a turntable 11 in such a manner as to be coaxial therewith. Three pressing pieces 13 and three steel balls 14 are disposed under this center boss 12. Each of the pressing pieces 13 and the steel balls 14 is partly exposed therefrom. The pressing pieces 13 are arranged at an angular interval of 120.degree., and the steel balls 14 are arranged at the same angular interval.
Further, the chucking device 10 is connected to a spindle motor 1 mounted on a chassis (not shown), and is driven by the motor 1 to rotate.
As illustrated in FIGS. 6A and 6B, an O-shaped ring (hereunder referred to as an O-ring) 16 made of an elastic material is mounted on the outer surface of a sleeve 15 coaxially connected to a central portion in the center boss 12. This O-ring 16 outwardly pushes the pressing pieces 13 and the steel balls 14 (namely, in the directions of arrows a and b shown in FIGS. 6A and 6B).
Further, each of the pressing pieces 13 is connected to the bottom portion of a corresponding sleeve 15 through a corresponding elastic piece 13s formed on the bottom portion thereof.
In the case of the aforementioned chucking device 10, when a disk D, whose central hole has engaged the center boss 12 as shown in FIG. 6A, is downwardly moved, the pressing pieces 13 inwardly move (namely, in the direction of an arrow a'). Thus, the inner edge of the central hole of the disk D is pressed outwardly (namely, in the direction of the arrow a) by an elastic restoring force of the O-ring 16. Consequently, the disk D is centered on the turntable 11.
Further, when the disk D is downwardly moved, the inner edge of the central hole of the disk D surmounts the steel balls 14 pushed outwardly (namely, in the direction of the arrow b) by the O-ring 16, as illustrated in FIG. 6B. The steel balls 14 push down the inner edge portion of the disk D (in the direction of an arrow C), so that the disk D is caught on the balls 14 and held by the turntable 11.
Namely, the chucking of the disk D is performed by the steel balls 14.
The steel balls 14, however, push the inner edge portion of the disk D from an upwardly slanting direction, as illustrated in FIG. 6B. Thus, the aforementioned conventional chucking device 10 has drawbacks in that the pressing forces of the steel balls 14 against the disk D vary with the shape of the chamfered inner edge thereof and that the adjustment of the pressing forces is difficult.
Moreover, the disk D is installed therein against the pressing forces of the steel balls 14. Thus, the conventional disk chucking device 10 has another drawback in that, if the pressing forces of the steel balls 14 against the disk D are increased, a large force is needed when the disk D is inserted thereinto or removed therefrom.
To eliminate this drawback, there has been proposed a disk chucking device adapted to optionally set a clamping force by pressing down the edge portion of the central hole of a disk at an end of a clamping lever pushed by a tension spring.
(Configuration of the Proposed Disk Chuck Device)
As shown in FIG. 7, this proposed disk chucking device 20A comprises a turntable 21A, a center boss 31C coaxially engaging therewith, and holding members 71 each of which includes a .GAMMA.-shaped clamping member 61 for chucking a disk and which accommodates and holds this clamping member 61.
Three notches (or openings) 22 are disposed at an angular interval of 120.degree. in an intervening portion between the outer and inner edges of the turntable 21A. A cylinder 23 is disposed in a central portion of the turntable 21A. Further, three catching bosses 29 are disposed on the bottom side of the turntable 21A at an angular interval of 120.degree. so that each of the catching bosses 29 is aligned with a corresponding one of the openings 22.
Three notches (or openings) 32 are arranged at an angular interval of 120.degree. in the center boss 31C, which engages the cylinder 23, in such a manner that each of the openings 32 is aligned with a corresponding one of the openings 22 of the turntable 21A. Each of three projection pieces 33 for centering a disk D is disposed between a corresponding pair of the openings 32.
In this proposed device, a cam 34 is provided on the inner surface of each of the openings 32 of the center boss 31C in such a manner as to be in opposed contact with a pin 64 of a corresponding one of the clamping members 61, as will be described later.
A chuck end portion 62 for chucking a disk is formed at the top portion of each of the clamping members 61 in such a manner as to project in the direction of the outer circumference of the turntable 21A and as to have upper and lower inclined surfaces. The pin 64 is disposed under this chucking portion 62. Further, a supporting shaft 63 is disposed at the bottom portion of each of the clamping members 61.
Each of the clamping members 61 is coupled to a corresponding one of the catching bosses 29 through a tension spring 66 and is inserted into a corresponding one of the holding members 71 provided on the bottom side of the turntable 21A.
The holding members 71 are mounted on the side surface of the cylinder 23 at an angular interval of 120.degree. so that each of the members 71 is aligned with and partly exposed from a corresponding one of the openings 22 of the turntable 21A.
Further, each of the clamping members 61 respectively inserted into the holding members 71 is disposed in such a way as to be able to be partly exposed from a corresponding one of the openings 32 of the center boss 31C.
Incidentally, the chucking device 20A illustrated in FIG. 7 is connected to the spindle motor 1 mounted on the chassis (not shown), and is driven by the motor 1 to rotate.
With the aforesaid configuration, the proposed chucking device 20A is adapted so that, when no disk is installed therein, the chuck end portion 62 of each of the clamping members 61 is exposed from the corresponding opening 32 of the center boss 31C in the direction of the outer periphery of the turntable 21A, as illustrated in FIG. 8A.
Further, each of the clamping members 61 is pushed downwardly (namely, in the direction of an arrow d shown in FIG. 8A) by the resilient force of the corresponding tension spring 66 stretched between the corresponding one of the catching bosses 29 provided on the bottom side of the turntable 21A and a catching hole 65 of a corresponding one of the clamping members 61. The corresponding supporting shaft 63 abuts against the bottom end of a guide groove 75 of a corresponding one of the holding members 71. The corresponding one of the clamping members 61 is pushed clockwise (namely, in the direction of an arrow e), so that the corresponding pin 64 abuts against the catching portion 73 of the corresponding holding member 71.
Incidentally, in FIGS. 8A to 8C and 9A to 9C, the supporting shaft 63 of the corresponding clamping member 61 is denoted by a mark "+" indicating the center of rotation. The pin 64 is designated by a mark ".times." indicating that the pin 64 is movable.
Further, for simplicity of drawing, only parts needed for describing the displacement of the clamping member 61 are denoted by reference characters in FIGS. 8B, 8C, 9B and 9C.
As illustrated in FIG. 8B, when a disk D is installed therein, the inner edge portion thereof pushes the top surface 62A of the chuck end portion 62 of each of the clamping members 61 in the inner circumference of the turntable 21A with the descent of the disk D (in the direction of the arrow d). Thus, each of the clamping members 61 is turned counterclockwise as viewed in this figure, so that each of the pins 64 is detached from the catching portion 73 of the corresponding holding member 71.
In a state of the device illustrated in FIG. 8B, each of the clamping members 61 remains pushed downwardly by the elastic force of the corresponding tension spring 66. Thus, the corresponding supporting shaft 63 abuts against the bottom end of the guide groove 75 of the corresponding holding member 71.
This state lasts until the disk D descends still more to a position where the inner edge of the top surface thereof surmounts the edge of the chuck end portion 62 of each of the clamping members 61.
Then, as illustrated in FIG. 8C, when the disk D descends still more and the disk D is put on the turntable 21A, the top surface of the disk D abuts against the inclined lower surface 62B of each of the clamping members 61.
In a state illustrated in FIG. 8C, each of the clamping members 61 remains pushed downwardly by the resilient force of the corresponding tension spring 66. Thus, the corresponding supporting shaft 63 abuts against the bottom end of the guide groove 75 of the corresponding holding member 71. Moreover, the supporting shaft 63 is pushed counterclockwise as viewed in this figure, so that the corresponding pin 64 abuts against the catching portion 73 of the corresponding holding member 71 again.
Thus, the inclined lower surface of the chuck end portion 62 of each of the clamping members 61 abuts against the inner edge portion of the disk D from above and pushes and clamps the disk D. Namely, the disk D is chucked.
Therefore, the setting of the elastic force of the tension springs 66 ensures a stable pressing force of each of the clamping members 61 when a disk D is installed in this proposed chucking device 20A.
Moreover, the relatively simple structure of each of the clamping members 61 and the holding members 71 results in decrease in the cost of components and in the number of man-hours to fabricate the device 20A.
Additionally, the supporting shaft 63 of each of the clamping members 61 is vertically rockably held in the guide groove 75 of the corresponding holding member 71. Thus, even when, for instance, a mechanical shock causes the disk D to move in the direction in which the chuck end portion 62 of each of the clamping members 61 engages therewith, the chuck end portion 62 thereof rises with the result that the pressing force against the disk D is constant.
In the case that a disk D is released from the chucking device 20A which is in the state where the disk is chucked as illustrated in FIGS. 8C and 9A, the bottom surface 62B of the chuck end portion 62 of each of the clamping members 61 is upwardly pushed by the inner edge of the top surface of the disk D with ascent thereof.
Further, as illustrated in FIG. 9B, each of the clamping members 61 is raised against the resilient force of the tension springs 66. The supporting shaft 63 thereof upwardly slides in the guide groove 75 of the corresponding holding member 71. Moreover, the pin 64 of each of the clamping members 61 is detached from the catching portion 73 of the corresponding holding member 71 and then abuts against the inner slope of the corresponding cam 34 of the center boss 32.
In the state of the device illustrated in FIG. 9B, the pin 64 of each of the clamping members 61 slides on the inner slope of the corresponding cam 34 of the center boss 32. Thus, each of the clamping members 61 rotates counterclockwise, as viewed in this figure.
The amount of rotation of each of the clamping members 61 reaches a maximum value when the disk D rises still more to a position where the inner edge of the top surface thereof surmounts the edge of the chuck end portion 62 thereof, as illustrated in FIG. 9C.
In the state of the device illustrated in FIGS. 9B and 9C, the chuck end portion 62 of each of the clamping members 61 is upwardly exposed from the corresponding opening 32 of the center boss 31C.
When the disk D rises still more from the position thereof shown in FIG. 9C to a position where the inner edge of the bottom surface thereof abuts against the top surface of the chuck end portion 62 of each of the clamping members 61, the engagement of the disk D with the chucking portion 62 is canceled.
Then, the supporting shaft 63 of each of the clamping members 61 downwardly slides in the guide groove 75 of the corresponding holding member 71 and finally abuts against the bottom end thereof because the clamping members 61 are pushed clockwise (namely, in the direction of the arrow e) and downwardly (namely, in the direction of the arrow d) by the resilient force of the tension springs 66. Moreover, each of the pins 64 abuts against the catching portion 73 of the corresponding holding member 71 again. Thus, the device 20A automatically returns to the initial state where no disk is installed therein as illustrated in FIG. 8A.
The aforementioned chucking device 20A, however, cannot be applied to a slim disk apparatus, because the holding members 71 are placed under the turntable 21A, as shown in FIGS. 7 to 9C.